Thermoplastic compositions consisting of blends of ground vulcanized rubber and olefin polymer are known; see U.S. Pat. No. 5,157,082. That patent discloses improved compositions comprising a blend of ground vulcanized rubber and a olefin polymer obtained by the incorporation of a functionalized olefin polymer. However, there is a definite need for improved blends of ground vulcanized rubber and olefin polymer in light of the large number of discarded tires and waste rubber articles which are not being reclaimed. As will be shown in a comparative example below, the mechanical properties of the '082 compositions (i.e. % elongation at break) are inferior relative to the mechanical properties of the compositions of the subject invention.
The quality of a rubber-plastic blend depends partly upon the mutual compatibility between the two components. When an olefin polymer and a rubber polymer are incompatible (such as when an olefin polymer and ground vulcanized rubber from tires are mixed) poor mechanical properties result when the mixing occurs without compatibilization. However, a wide range of properties can be obtained when different compatibilizers are used. Much work is being done to continue to apply the principles of compatibilization to develop new blends of different materials which are normally incompatible. This includes the compatibilization of ground vulcanized rubber/polymer blends to improve blend properties. Therefore, if the compatibilization of the ground vulcanized rubber/olefin polymer blend can be improved, improved compositions would be obtained.